This invention relates generally to gas turbine engines, and more particularly, to methods for replacing turbine shroud supports.
At least some known gas turbine engines include a core engine having, in serial flow arrangement, a fan assembly and a high pressure compressor which compress airflow entering the engine, a combustor ignites a fuel-air mixture which is then channeled through a turbine nozzle assembly towards low and high pressure turbines which each include a plurality of rotor blades that extract rotational energy from airflow exiting the combustor.
The turbine nozzle assemblies are positioned between adjacent rows of rotor blades and channel airflow downstream towards the rotor blades. More specifically, at least some known turbine nozzles include vanes that extend radially between an inner and an outer band. Each nozzle assembly is coupled to casing surrounding the rotor assembly by a plurality of hook assemblies that extend outwardly from the outer band. More specifically, at least some known nozzle assemblies are coupled to the casing through a shroud support.
During engine operation, stresses may be induced to the shroud support through from the nozzle vane assemblies. Over time, continued exposure to such stresses may cause cracking the shroud support. Continued operation with such cracking may cause premature failure of the shroud support. Accordingly, to facilitate preventing such premature failure, shroud supports are routinely inspected for cracking.
Current repair methods include welding the cracks using a gas tungsten arc welding process. However, such techniques are time consuming as each welding process requires a heat treatment before the support may be returned to service. Furthermore, although such a process may restore the part to a base condition, occasionally, such a process may actually result in excessive shrinkage of the shroud segment which over time may cause promote increased cracking, and a subsequent decrease in the useful service life of the shroud support.